Petabits/sec, and the like

Nicholas Henke henken at
Wed Nov 5 13:03:51 EST 2003

On Wed, 2003-11-05 at 12:40, Jim Lux wrote:
> All of the enjoyable chat about achieving stupendous data rates with disk 
> drives in trucks is quite interesting. By the way, I don't know why you 
> insist on having the drives mounted in racks..why not just leave them in 
> their original shipping containers. There's also the concept of how many 
> bits are being moved in, say, a container load of Britney Spears DVDs. 
> (leaving aside questions about redundancy, information entropy, and whether 
> there is any information content in Britney Spears to begin with)

> For example.... old style 10Mbps thinnet ethernet used solid dielectric 
> coax, which had a propagation velocity of about 0.66 c.  twisted pair is 
> probably around 0.75, fiber optics are a bit tricky, depending on the mode 
> of propagation, but probably around 0.85.  The pickup truck full of disks 
> is about 1E-7.  The units of the new measure would be, what, (bits per 
> second)*(meters per second) or bit meters per second squared. I'd normalize 
> by c, to make the units more useful..I'd modestly propose calling the new 
> unit the Lux, but it's already been used, so perhaps we should recognize 
> rgb's contributions by calling it the "Brown"  10Mbps over thinnet would 
> then be 6MegaBrowns.  100mbps over twisted pair would be 70MegaBrowns.  The 
> 1 Pb/s truckload of disks would be 100MegaBrowns.

Couldn't resist -- 'What can Brown do for you' ?

Nicholas Henke
Penguin Herder & Linux Cluster System Programmer
Liniac Project - Univ. of Pennsylvania

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